The exploration for oil and gas is being extended to great depths, with a commensurate demand upon drill rig capabilities, said demands exceeding human capabilities and/or endurance. For example, remotely controlled tools and equipment have replaced manually operable tongs and elevators and the like, and for instance extensible arms are used to manipulate stands of drill collar and drill pipe into and out of alignment with the central axis of the well. Generally, offshore drilling rigs have derricks of greater size than those of land rigs, and because of the rigors imposed by offshore inclement weather said offshore rigs are most highly automated; and to these ends offshore derricks are of greater girth and afford more space for said automation, at the "derrickman" platform and at the "derrick floor hand" with which this invention is concerned, particularly those tools which manipulate the stands of drill collar and drill pipe and the like into and out of working position. In this respect, it is an object to provide improved oil well tools for mechanical control of said stands within the derrick confines, and especially within the smaller confines of existent land based rigs to which this equipment is retrofitted with facility.
Heretofore, extensible cylinder and piston units have been used at both the derrick floor and at the derrickman's level, and mounted so as to slew the collar and pipe stands into the desired positions. These tools have not been completely satisfactory in that they tend to be cumbersome and slow moving and require additional tools such as "finger guides" and which must be separately controlled. And, due to the restricted cross section at the elevated platform level, it is most common that such devices project through and from the exterior of the rig. It is an object of this invention to confine this tool within the rig. Furthermore, prior art tools at the derrickman level have not operated so as to place or retrieve stands fully from within the finger slots, as it is an object herein to do so with facility, and even within the confines of the smaller land rigs and/or masts.
The "derrickman" level or platform is usually 86 feet above the derrick floor when running 90 foot stands, and is comprised of a "monkeyboard" extending from the off draw works side of the derrick toward the center and terminating short of the space through which the traveling block passes, and a pair of "fingerboards" are at each side of the monkeyboard and with slots normal to the monkeyboard to receive the upper end portions of the stands extending therebetween and into and out of the slots. The slots are narrow (51/2 inches), and it is therefore an object of this invention to provide a stand positioning tool referred to herein as a "derrickman" having an active stand engaging gripper head no wider than the distance between the two next adjacent stands between which it moves to place a stand or retrieve the same. To this end there is provided extensible arms traveling the length of the monkeyboard and rotatable on a vertical axis to project a gripper head into engagement with the stand so as to position the same. The significant features of this invention are, that the carriage therefor is no greater in width than the monkeyboard in the case of the derrickman, and that the extensible arms and gripper head are no greater in width than the space between adjacent stands.
The diameters of drill collar and drill pipe run by drilling rigs varies greatly and it is therefore an object of this invention to accomodate a range of sizes thereof by the gripper head of the automated tool as hereinafter disclosed. For example, collar and drill pipe used in a rig will vary from 31/2 inch diameter to 111/4 inch diameter, and though gripper jaws can be made to accomodate each particular size the jaws according to the present invention are such as to accomodate a range of sizes. In practice, one gripper jaws are such as to embrace the smaller range of 31/2 to 5 inch diameter pipe, while another gripper jaws are such as to embrace the larger range of 5 inch to 111/4 inch diameter pipe, or collars as the case may be. It is to be understood however, that any range of size may be adapted to. A feature of this invention is the combination of the two or more aforesaid gripper jaws within confines of the one gripper head, whereby a full range of pipe sizes is accomodated.
In view of the foregoing, it is an object to provide a reinforced monkeyboard characterized by a track disposed for travel of the carriage coextensive therewith. It is also an object to provide a turret confined within the width of said carriage to carry the extensible arms on a vertically disposed axis. It is also an object to provide extensible arms that retract together in order to conserve space. And it is also an object to provide means incorporated within said extensible arms to maintain a substantially vertical disposition of the gripper head axis in parallel relation to said vertical turret axis, and derrick axis as well, and for alignment within the aforesaid finger slots. Still another object of this invention is to automate each of the aforesaid functional means, all within the structural confines thereof, and by means of hydraulics for the positive actuation thereof and accurate placement of the stands of drill collar and pipe to be positioned thereby. In practice, short stroke cylinder and piston units are employed and the motion thereof augmented with gearing and/or cams, with limiting means for remote control and precision operation of the rectilinear, rotary and lever actions coordinated, all as hereinafter described.